Neonatal incubator humidifier system

ABSTRACT

A humidifier system for humidifying a microenvironment in a neonatal incubator includes a reservoir configured to hold water to be evaporated for humidifying the microenvironment. A chamber divider defines a heating chamber within the reservoir, and a movable heating element is positioned at a surface level of the water inside the heating chamber so as to heat the water at the surface level inside the heating chamber. The heating element is configured such that it is moved downward within the heating chamber so as to maintain the heating element at the surface level of the water as an amount of water in the reservoir decreases.

BACKGROUND

The present disclosure generally regards incubator systems providing amicroenvironment for a neonate, and more specifically to a neonatalincubator having a humidifier system configured to reduce sound levelsgenerated due to heating the evaporant.

Neonatal incubators create a microenvironment that is thermally neutralwhere a neonate can develop. These incubators typically include ahumidifier and associated control system that controls the humidity inthe neonatal microenvironment. The humidifier comprises a device thatevaporates an evaporant, such as distilled water, to increase relativehumidity of air within the neonatal microenvironment. Such humidifierstypically have an evaporant source in the form of a reservoir that holdswater to be dispersed into the microenvironment within the incubator.For example, the humidifier may be a steam humidifier or vaporizer inwhich the water is heated to cause evaporation. The humidifier istypically controllable such that the amount of water, or water vapor,added to the microenvironment is adjustable in order to control thehumidity to a desired value.

SUMMARY

This Summary is provided to introduce a selection of concepts that arefurther described below in the Detailed Description. This Summary is notintended to identify key or essential features of the claimed subjectmatter, nor is it intended to be used as an aid in limiting the scope ofthe claimed subject matter.

One embodiment of a humidifier system for humidifying a microenvironmentin a neonatal incubator includes a reservoir configured to hold water tobe evaporated for humidifying the microenvironment. A chamber dividerdefines a heating chamber within the reservoir, and a movable heatingelement is positioned at a surface level of the water inside the heatingchamber so as to heat the water at the surface level inside the heatingchamber. The heating element is configured such that it is moveddownward within the heating chamber so as to maintain the heatingelement at the surface level of the water as an amount of water in thereservoir decreases.

One embodiment of a neonatal incubator comprises a bed configured tosupport a neonate and a hood above the bed configured to encapsulate amicroenvironment around the neonate. A humidifier system is configuredto control humidity of the microenvironment, the humidifier systemhaving a reservoir configured to hold water to be evaporated forhumidifying the microenvironment, and a heating chamber divider defininga heating chamber within the reservoir. A movable heating element ispositioned at a surface level of the water inside the heating chamber soas to heat the water at the surface level inside the heating chamber.The heating element is moved downward within the heating chamber so asto maintain the heating element at the surface level of the water as anamount of water in the reservoir decreases.

Various other features, objects, and advantages of the invention will bemade apparent from the following description taken together with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the best mode presently contemplated of carryingout the disclosure. In the drawings:

FIG. 1 is a perspective view of an exemplary incubator containing ahumidifier system, including a schematic diagram depicting relevantsensing and control elements for the humidifier system.

FIG. 2 is a schematic depiction of a reservoir in an incubator systemhaving an exemplary heating element and configuration according to oneembodiment of the present disclosure.

FIG. 3 depicts one embodiment of a puck-shaped heating element accordingto one embodiment of the present disclosure.

FIG. 4 is a schematic depiction of a reservoir in an incubator systemcomprising another embodiment of a heating element and configuration.

FIG. 5 is a schematic depiction of a reservoir in an incubator systemcomprising yet another exemplary heating element and configuration.

DETAILED DESCRIPTION

Through extensive experimentation and research in the field of neonatalincubators, the present inventor has recognized that present incubatorsystems using heated water generate too much noise. The high noiselevels generated by current humidifier systems can negatively affect aninfant housed in the incubator. Neonates are known to be detrimentallyaffected by increased sound levels inside the microenvironment of anincubator. The inventor has recognized that the sound level in anincubator can be significantly reduced by changing existing humidifiersystems to reduce or eliminate bubbling, or boiling, of the water.Present incubator systems heat the water at the bottom of the reservoir,causing the water to boil up to the top. This boiling generates abubbling sound, which sometimes can be quite loud and the greatestsource of noise generation in the incubator.

The disclosed system significantly reduces or eliminates the soundcaused by the boiling water by only heating the water surface and notheating water in the lower portion of the reservoir, thereby eliminatingthe bubbling sound. The disclosed humidifier system implements a movableheating element that is maintained at a surface level of the water. Inone embodiment, the heating element is contained in a heating chamberwithin the reservoir and is positioned to just heat the water at thesurface level inside the heating chamber. The heating element isconfigured so that it can be maintained at or near the water surfacesuch that only water near the water surface boils and water located in alower portion of the heating chamber does not boil.

The heating element is thus shorter, or thinner, compared to heatingelements implemented in prior art systems where the heating wasconcentrated in a lower portion of the reservoir, creating the boilingaction. Existing humidifier systems include one or more heating rodsthat extend to the bottom of the reservoir, wherein the heating elementoccupies at least the bottom third of the heating rod, or more. Oneexample of an existing heating element includes a stainless steel rodthat extends down into the reservoir, wherein one or more heatingelements transmit heat to the water from the bottom portion of the rod,such as the bottom third or bottom half of the rod length. The watersurrounding the bottom portion of the rod is heated to a boiling point,causing bubbles to rise from the bottom to the top of the waterreservoir. The noise from the boiling action echoes within the reservoirand surrounding chambers, thus making the boiling sound pronounced forthe infant. Moreover, such existing systems heat large volumes of waterin order to cause evaporation, which is inefficient.

In the disclosed system, the shorter heating element is moved downwardas the amount of water in the reservoir decreases such that the heatingelement is always maintained at the surface level of the water. Theheating element may be configured and maintained at the surface level byvarious means, examples of which are described herein. In oneembodiment, the heating element is configured such that it floats on thewater surface. In other embodiments, a mechanism, such as a spring or alead screw, works in combination with the buoyancy force of the water inorder to maintain the heating element at the surface level.

FIG. 1 depicts one embodiment of an incubator system 1 having a bed 16supported by a base 2. In the depicted embodiment, the base 2 is onwheels to facilitate transit of an infant in the incubator system 1. Thedepicted incubator system 1 has a hood 10 defining a chamber 12 creatinga microenvironment for housing a neonate. The hood 10 comprises atransparent housing extending above the bed 16. In the example, the hood10 includes a plurality of portholes 14 through which a healthcareprovider may access the one or more infants within the chamber 12. Thedepicted hood 109 comprises a single structure movable as a unit. Inother implementations, sidewalls of the hoods 10 may remain about thebed 16 forming a crib, wherein the top-most portion is separable and/orremovable from the sidewalls to access the one or more infants supportedin the microenvironment.

The bed 16 may further include heating component(s) 30 used to controlthe temperature within the microenvironment of the chamber 12. Forexample, the chamber heater 30 may be a radiant heating or warmingdevice that heats the air within the chamber 12 to a predefinedtemperature or within a predefined temperature range. In anotherembodiment, the heater 30 may comprise a convective or conductiveheating device or any other type of controllable heating or warmingdevice.

The incubator system 1 further includes a humidifier system 4controllable to adjust the relative humidity within the chamber 12. Thehumidifier comprises a device that evaporates water, such as distilledwater 7, to increase relative humidity of air within the neonatalmicroenvironment. The humidifier system 4 has a water reservoir 6containing evaporant, such as distilled water, utilized forhumidification of the chamber 12. The water reservoir 6 is a tank orother vessel capable of holding the evaporant. Although the waterreservoir 6 in the illustrated embodiment is located below the bed 16,in other embodiments the water reservoir 6 may be provided at otherlocations. In one embodiment, the water reservoir 6 is removable fromthe incubator system 1 for draining and/or cleaning purposes. In otherembodiments, the reservoir 6 may remain attached to the incubator system1 and may provide other access for the purpose of draining the evaporantfrom the reservoir 6 and/or cleaning the reservoir 6. A water levelsensor 18 may sense the water level within the reservoir 6 and generatea water level indicator value, such as to modify a clinician that waterneeds to be added to the reservoir 6. Additionally, one or more sensorsmay be provided to sense temperature and humidity within themicroenvironment of the chamber 12, such as humidity sensor 19 andtemperature sensor 20.

The sensors 18, 19, 20 provide the sensed information to the controlsystem 35, which controls various elements within the incubator system1. The control system 35 includes a computing system having a processorand a memory capable of storing software for providing various controlfunctions, including for controlling the humidifier in order to maintaina particular humidity level within the chamber 12. In the depictedembodiment, the incubator system 1 further includes a user interface 39comprising a display 24, a speaker 26, and an input 40. Such userinterface 39 elements are used to provide information to a clinicianregarding the status and condition of the incubator system 1, as well asto receive control inputs from a clinician to control various aspects ofthe incubator system 1, including to control the environment within thechamber 12. The display 24 includes any visual output device, examplesof which include a digital display screen, monitor, or the like (whichmay also be a touchscreen) that presents visible notifications ormessages to a clinician.

The display 24 may include a monitor independent of the bed portion ofthe incubator incorporated into some portion. In another implementation,the display 24 may comprise a screen of a portable computing orelectronic device, such as a smartphone or tablet computer. Likewise,the speaker 26 may be any audio output device and may be incorporatedinto the bed portion of the incubator system, or may be included in aseparate device, such as in the personal computing device describedabove. Likewise, the input 40 may be any device that facilitates userinput of information, such as commands, selection, data, or settings forthe incubator system 1. In one implementation, the input 40 may includea keyboard, touchpad, touchscreen, mouse, or microphone with speechrecognition software, or the like. Thus, the user interface 39 may beconfigured to allow a user, such as a clinician, to set a humidity levelfor the microenvironment, and the control system 35 controls operationof the humidifier 4 to maintain the humidity at the selected humiditylevel. To provide just one example, the user interface may be configuredto allow a clinician to set a relative humidity percentage for themicroenvironment, such as a humidity level between 30% and 95%. Thecontrol system 35 then generates control instructions to control currentto one or more heating elements within the humidifier system 4 in orderto control the amount of water evaporated from the reservoir, andthereby to control the humidity level in the microenvironment within thechamber 12.

FIG. 2 represents one embodiment of a humidifier reservoir 6 and heatingelement configuration. A small heating element 60 is suspended at asurface level 41 of the water 7 inside the reservoir 6. As the amount ofwater 7 in the reservoir 6 decreases due to its evaporation, the heatingelement 60 moves downward such that it is maintained at the surfacelevel 41 of the water 7. The surface level 41 of the water 7 is alignedwith the water surface 42, such that a bottom side 62 of the heatingelement 60 is maintained at or below the water surface 42 and a top side61 of the heating element 60 is maintained above the water surface 42.

In the depicted embodiment, a heating chamber 50 is defined within thereservoir 6, which reduces the amount of water exposed to the heatingelement 60 and thus provides more efficient evaporation. The heatingchamber 50 is defined by a chamber divider 48, which partitions a spacewithin which the heating element 60 moves as the water 7 in thereservoir 6 is depleted and the surface level 41 moves down. In oneembodiment, the chamber divider 48 is comprised of a thermally resistantmaterial, such as plastic, in order to maintain the heat from theheating element 60 within the water in the heating chamber 50 as much aspossible. The heating chamber 50 may be defined at any location withinthe reservoir 6, which may be within a center portion or an edge portionof the reservoir 6.

The heating element 60 moves up and down within the chamber 50 toaccommodate a range of surface levels 41, from a highest level in linewith the maximum fill level 45 to a lowest level in line with theminimum fill level 44. In one embodiment, the chamber divider 48 has abottom edge 49 configured to stop the heating element 60 when thesurface level 41 has gotten too low, such as the minimum fill level 44.In one embodiment, the humidifier system 4 is configured to shut offwhen the heating element 60 reaches the bottom edge 49 of the chamberdivider 48. In other embodiments, the humidifier system 4 may beconfigured to shut off when the surface level 41 reaches somepredetermined point before the heating element 60 reaches the bottomedge 49, such that the heating element 60 never reaches the bottom edge9 when the humidifier system 4 is operating.

In one embodiment, the heating element 60 is moved up and down along aguide 56, such as a rod. The guide 56 may be suspended from a topelement 54 and span from a top portion 51 of the chamber 50 to a bottomportion 52 of the chamber 50. The guide 56 spans at least a distance toguide the heating element 60 from a maximum fill level 45, where amaximum amount of water 7 is in the reservoir 6, and a minimum filllevel 44, where a minimum amount of water 7 is contained in thereservoir 6. In one embodiment, the heating element 60 is configuredwith a hole 64 (FIG. 3) that allows the heating element 60 to move upand down with respect to the guide 56. The guide 56 may be configuredsuch that it prevents lateral movement of the heating element 60 butallows easy vertical movement. For example, the heating element 60 mayhave a hole 64 with a diameter D_(H) that is only slightly larger than adiameter of the guide 56. Thereby, the heating element 60 is maintainedin a centered position within the chamber 50 and prevented fromimpacting the chamber divider 48, which could cause additional noise andalso make the heating less efficient where the portion of the heatingelement 60 contacting the chamber divider 48 is not in contact with thewater 7. However, in other embodiments no guide is provided (e.g. FIG.5).

The heating element 60 may be any of various shapes capable of beingsuspended at the surface level 41. As exemplified in FIG. 3, the heatingelement 60 may be puck-shaped, or cylindrical, having a top side 61 thatis above the water surface 42 and the bottom side 62 that is at orslightly below the water surface 42. The puck-shaped heating element 60has a length L_(p) between the top side 61 and the bottom side 62. Thelength L_(p) may vary; however, the heating element 60 is generallyshort such that the heating element 60 does not extend deep into thewater 70 so as not to cause the bubbling effect described above. In oneexemplary embodiment, the length L_(p) of the heating element 60 may be20 mm or less. In another embodiment, the length L_(p) of the heatingelement 60 may be 15 mm or less, or may be 12 mm or less. Minimizing thelength L_(p) is desirable to heat only the water surface 42. In thedepicted embodiment, the heating element 60 has a hole 64 in the center,wherein the hole has a diameter D_(H). In other embodiments, the heatingelement 60 may not have any hole, and thus may not be configured toslide along a guide 56. The puck-shaped heating element 60 has adiameter D_(p). The diameter D_(p) may be any size, depending on theoperational demand for which the humidifier system 4 is configured. Inone exemplary embodiment, the diameter D_(p) of the puck-shaped heatingelement 60 is 25 mm or less.

In other embodiments, the heating element 60 may be shaped differently.For instance, the heating element may be spherical, or may otherwisehave a curved bottom side 62 and/or top side 61. In other embodiments,the heating element may be cone-shaped having a point that extends belowthe water surface 42. In still other embodiments, the heating element 60may be rectangular or a cube.

The chamber 50 is sized to accommodate the heating element 60. Thus,where the heating element 60 is puck-shaped, the chamber is cylindrical.In an embodiment where the heating element 60 is a square or arectangle, the heating chamber 50 may have the same shape. Thedimensions of the heating chamber 50 may generally follow those of theheating element 60, being slightly larger so as to permit the heatingelement 60 to move freely up and down within the chamber 50 and allowinga small amount of water to fill a gap between the heating element 60 andthe chamber divider 48. To provide just one example, a distance of atleast 1.5 mm may be maintained between the surrounding edge of theheating element 60 and the chamber divider 48.

The heating element may be maintained at the surface level 41 of thewater 7 by various means or mechanisms. In some embodiments where therelative density of the heating element is greater than that of water,the heating element 60 will sink without some mechanism providing anupward force on the heating element 60. Referring again to FIG. 2, theweight of the heater F_(H) must be counteracted by an upward forceacting on the heating element 60. The water 7 provides a buoyancy forceF_(B) that pushes up on the heating element 60. In some embodimentswhere the relative density of the heating element is lower than that ofwater, the buoyancy force F_(B) will be enough to maintain the heater atthe surface level 41. In other embodiments, like that depicted in FIGS.2 and 3, an additional mechanism is needed to compensate for thedifference between the downward-acting weight of the heater F_(H) andthe upward-acting buoyancy force F_(B). In FIG. 2, a tension spring 66connects between the top of the reservoir 6 and/or the top element 54and the heating element 60 in order to provide an upward-acting springforce F_(S) that, in conjunction with the buoyancy force F_(B),counteracts the weight F_(H) of the heating element 60. Accordingly, aspring 66 is chosen that provides a spring force F_(S) calibrated tocompensate for the difference between the heater weight F_(H) and thebuoyancy force F_(B) so that the heating element 60 is maintained at thesurface level 41. Moreover, the tension spring 66 is configured suchthat it provides a constant spring force F_(S) on the heating elementacross a range of water levels 42 between the maximum fill level 45 andthe minimum fill level 44.

In another embodiment, the additional vertical force needed tocounteract the heater weight F_(H) may be provided by threads 57 on theguide 56. In other words, the guide 56 may be a lead screw with threads57 provided at angles calibrated to provide an upward force equal to thedifference between the heater weight F_(H) and the buoyancy force F_(B).The thread angles of the threads 57 may be steeper (a higher angle asmeasured from horizontal) to provide a lesser upward force or less steepto provide a greater upward force. In certain embodiments, the interiorside of the hole 64 in the heating element 60 may be threaded tocorrespond to the thread angle of the threads 57 on the guide 56 suchthat the heating element 60 remains level and parallel with the watersurface 42. Accordingly, the heating element 60 rotates downward on thelead screw guide 56 as the amount of water 7 in the reservoir 6decreases.

FIG. 5 depicts another embodiment where the heating element 60 has alower relative density than water such that the heater weight F_(H) isless than the buoyancy force F_(B). For example, the heating element 60may be a silicon heater where a heating coil or wire is encased insilicon, such as a silicon disk to form a puck-shaped heating element 60similar to that depicted at FIG. 3. In various embodiments, the buoyantheating element 60 may float freely within the heating chamber 50, ormay be held in place by a guide 56. Where no guide is used, the heatingelement 60 may be solid, i.e., without the hole 64 shown in FIG. 3.Where a guide 56 is present, the buoyant heating element 60 is providedwith a hole 64 therethrough such that the heating element 60 floats upand down with respect to the guide 56.

Power is provided to the heating element 60. In the depictedembodiments, wires 58 extend from the heating element 60 connecting tothe heating circuit therein. The wires 58 are provided with sufficientslack such that the heating element 60 can move freely within the rangeof surface levels 41 between the maximum fill level 45 and the minimumfill level 44. In the figures, the wires 58 are shown as having slackcontained within the heating chamber 50. In other embodiments, the wires58 may travel within the guide 56, where one is provided, and the guide56 may have one or more openings, or slots, running the length of theguide 56 (or at least between the maximum fill level 45 and minimum filllevel 44) such that the wires connect with the heating circuit withinthe heating element 60. In the spring embodiment, the wires may travelgenerally parallel with the spring 66.

In still other embodiments, the entire surface of the guide 56 isconductive and the interior surface of the hole 64 in the heatingelement 60 is configured to remain in contact with the guide 56 as theheating element 60 moves up and down within the heating chamber 50. Inanother example, contact strips or rings may be provided running thelength of the guide 56. In the spring embodiment depicted at FIG. 2, forinstance, positive and negative terminal strips may run the length ofthe guide 56, and the heating element 60 and guide 56 may be configuredsuch that the orientation of the heating element 60 remains fixed withrespect to the guide such that terminals on the heating element 60remain in contact with the terminal strips on the guide 56 as theheating element 60 moves up and down within the heating chamber 50. Inthe lead screw embodiment depicted at FIG. 4, for example, contactstrips may twist around the guide 56 parallel with the threads 57 suchthat corresponding terminals on the heating element 60 remain in contactwith the terminal strips.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope of the inventionis defined by the claims, and may include other examples that occur tothose skilled in the art. Such other examples are intended to be withinthe scope of the claims if they have structural elements that do notdiffer from the literal language of the claims, or if they includeequivalent structural elements with insubstantial differences from theliteral languages of the claims.

We claim:
 1. A humidifier system for humidifying a microenvironment in aneonatal incubator, the humidifier system comprising: a reservoirconfigured to hold water to be evaporated for humidifying themicroenvironment; a chamber divider defining a heating chamber withinthe reservoir; a movable heating element positioned at a surface levelof the water inside the heating chamber so as to heat the water atsurface level inside the heating chamber; and wherein the heatingelement is moved downward within the heating chamber as an amount ofwater in the reservoir decreases so as to maintain the heating elementat the surface level of the water.
 2. The humidifier system of claim 1,wherein the heating element is configured and positioned such that onlywater near the surface level boils and water located in a lower portionof the heating chamber does not boil.
 3. The humidifier system of claim1, wherein the heating element is puck-shaped, wherein a top side of thepuck-shaped heating element is maintained above a water surface andbottom side of the puck-shaped heating element is maintained at or belowthe water surface.
 4. The humidifier system of claim 3, wherein thepuck-shaped heating element has a hole configured to accommodate aguide, and wherein the puck-shaped heating element slides down the guideas it moves downward within the heating chamber.
 5. The humidifiersystem of claim 3, wherein the heating chamber is cylindrical.
 6. Thehumidifier system of claim 1, wherein the heating element is maintainedat the surface level of the water by a tension spring exerting a springforce calibrated based on a weight of the heating element and a buoyancyforce of the water on the heating element to maintain the heatingelement at the surface level as the amount of water in the reservoirdecreases.
 7. The humidifier system of claim 6, wherein the tensionspring is configured to provide a constant spring force on the heatingelement across a range of surface levels from a maximum fill level to aminimum fill level.
 8. The humidifier system of claim 1, wherein theheating element is configured to float on the water on the water insidethe heating chamber.
 9. The humidifier system of claim 8, wherein theheating element is a silicon puck, wherein a weight of the heatingelement is less than a buoyancy force of the water acting on the heatingelement.
 10. The humidifier system of claim 1, further comprising aguide that extends from a top portion of the heating chamber to a bottomportion of the heating chamber and through a hole in the heatingelement, wherein the guide is a leadscrew with thread angles calibratedbased on a weight of the heating element and a buoyancy force of thewater on the heating element to maintain the heating element at thesurface level as the amount of water in the reservoir decreases.
 11. Aneonatal incubator comprising: a bed configured to support a neonate; ahood above the bed configured to encapsulate a microenvironment aroundthe neonate; a humidifier system configured to control humidity of themicroenvironment, the humidifier system having: a reservoir configuredto hold water to be evaporated for humidifying the microenvironment; aheating chamber divider defining a heating chamber within the reservoir;a movable heating element positioned at a surface level of the waterinside the heating chamber so as to heat the water at surface levelinside the heating chamber; and wherein the heating element is moveddownward within the heating chamber as an amount of water in thereservoir decreases so as to maintain the heating element at the surfacelevel of the water.
 12. The neonatal incubator of claim 11, wherein theheating element is configured and positioned such that only water nearthe surface level boils and water located in a lower portion of theheating chamber does not boil.
 13. The neonatal incubator of claim 11,wherein the heating element is puck-shaped, wherein a top side of thepuck-shaped heating element is maintained above a water surface andbottom side of the puck-shaped heating element is maintained at or belowthe water surface.
 14. The neonatal incubator of claim 13, wherein thepuck-shaped heating element has a hole configured to accommodate aguide, and wherein the puck-shaped heating element slides down the guideas it moves downward within the heating chamber.
 15. The neonatalincubator of claim 13, wherein the heating chamber is cylindrical. 16.The neonatal incubator of claim 11, wherein the heating element ismaintained at the surface level of the water by a tension springexerting a spring force calibrated based on a weight of the heatingelement and a buoyancy force of the water on the heating element tomaintain the heating element at the surface level as the amount of waterin the reservoir decreases.
 17. The neonatal incubator of claim 16,wherein the tension spring is configured to provide a constant springforce on the heating element across a range of surface levels from amaximum fill level to a minimum fill level.
 18. The neonatal incubatorof claim 11, wherein the heating element is configured to float on thewater inside the heating chamber.
 19. The neonatal incubator of claim18, wherein the heating element is a silicon puck, wherein a weight ofthe heating element is less than a buoyancy force of the water acting onthe heating element.
 20. The neonatal incubator of claim 11, furthercomprising a guide that extends from a top portion of the heatingchamber to a bottom portion of the heating chamber and through a hole inthe heating element, wherein the guide is a leadscrew with thread anglescalibrated based on a weight of the heating element and a buoyancy forceof the water on the heating element to maintain the heating element atthe surface level as the amount of water in the reservoir decreases.